Airtac MFJ Adjustable Mini Cylinder MFJ40X40-20S
The AirTAC Airtac MFJ Adjustable Mini Cylinder MFJ40X40-20S is a genuine double acting, adjustable stroke JIS-standard round-body mini air cylinder with a Ø40mm bore and 40mm stroke, 1/4" air ports and a SUS304 stainless-steel barrel for mildly corrosive environments. For the same bore and stroke it is shorter than an ISO 6432 cylinder, saving mounting space.
- BoreØ40 mm
- Stroke40 mm
- Port size1/4"
- Acting typeDouble acting, adjustable stroke
- Rod threadM14×1.5
- CushionFixed TPU bumper pads
- No minimum order. A single piece can be ordered.
- Ready in 3–5 business days. That is the time we take to process the order and hand it to the carrier. Transit time after that depends on the destination.
About the Airtac MFJ Adjustable Mini Cylinder MFJ40X40-20S
Trimming the extend end by up to 20 mm on site, this double-acting JIS-standard round-body mini cylinder lets you dial in the exact stroke without buying a new unit or adding external stops. The MFJ40X40-20S uses a 40 mm bore with a 1/4" port and a 16 mm rod to deliver 628.3 N of push force at 0.5 MPa, yielding a safe working load of about 377 N or a 32 kg vertical lift with a 2:1 margin.
The riveted rolling-packed construction pairs a SUS304 stainless steel barrel with aluminium covers, resisting mild corrosion and washdowns while saving mounting length compared to an ISO 6432 cylinder. Because this SKU includes the -S magnet, it is ready for CMSG, DMSG, or EMSG reed and electronic switches. Fixed TPU bumper pads decelerate the stroke ends across the 30-800 mm/s speed range.
Airtac MFJ Adjustable Mini Cylinder MFJ40X40-20S Technical Specifications
| Model | Airtac MFJ Adjustable Mini Cylinder MFJ40X40-20S |
|---|---|
| Series | MFJ JIS mini cylinder |
| Bore size | Ø40 mm |
| Stroke | 40 mm |
| Acting type | Double acting, adjustable stroke |
| Port size | 1/4" |
| Rod thread | M14×1.5 |
| Fluid | Air (filtered by 40µm element) |
|---|---|
| Operating pressure | 0.15 – 1.0 MPa |
| Proof pressure | 1.5 MPa |
| Temperature | -20 to +70 °C |
| Speed range | 30 – 800 mm/s |
| Cushion | Fixed TPU bumper pads |
| Max standard stroke | Up to 500 mm |
Specifications follow the official AirTAC MF/MFC (JIS-standard) datasheet. Barrel: SUS304 stainless steel; covers: aluminum alloy (round-body, riveted rolling-packed construction). Thread options: PT (blank) / G / NPT.
Theoretical Output Force (Ø40mm)
| Pressure | Push force | Pull force |
|---|---|---|
| 0.5 MPa | 628 N | 528 N |
| 0.7 MPa | 880 N | 739 N |
| Max (@1.0 MPa) | 128 kgf | |
Actual usable force is lower than theoretical due to friction and back-pressure. Size with a safety margin.
Model Code: Airtac MFJ Adjustable Mini Cylinder MFJ40X40-20S
| MFJ | JIS-standard round-body mini cylinder (adjustable-stroke). |
|---|---|
| 40 | Bore size in mm. |
| ×40 | Stroke length in mm. |
| -S | Optional built-in magnet for CMSG / DMSG / EMSG sensors. |
MF-family variants: MF / MFC (double acting ±cushion), MSF / MTF (single acting push / pull), MFD / MFCD (double rod ±cushion), MFJ / MFCJ (adjustable stroke ±cushion). Back covers CA / U / CM. Mounting LB / FA / SDB / TC.
Where the Airtac MFJ Adjustable Mini Cylinder MFJ40X40-20S Is Used
Changeover Dial-In
Fine-tune the extend stroke up to 20 mm during product changeovers to set new end positions without machining fresh hard stops.
Prototype Trial Fits
Leverage the 628.3 N push force to test part placement in assembly rigs, adjusting the stroke on the fly until the exact kinematic distance is proven.
Variable Position Stops
Set precise ejection points for 32 kg payloads using the on-site adjuster, relying on the built-in magnet to confirm the retracted home position.
Is the Airtac MFJ Adjustable Mini Cylinder MFJ40X40-20S the Right Cylinder?
When sizing these adjustable cylinders, compare the two bores directly: the 40 mm bore here gives 628.3 N push at 0.5 MPa, while the smaller MFJ32 provides 402.2 N. Choose the 40 mm when moving heavier fixtures, and rely on the 20 mm adjuster window to fine-tune the extend position during line changeovers or trial fits where the final stop is not yet fixed. For mounting, use LB foot, FA flange, or TC trunnion brackets, as there is no SDB or back-cover option on this build.
Remember that the external adjuster only sets the end position; it is not a mid-stroke lock. The piston will drift if air is lost, so fit an external rod lock or pilot-operated check valve if you need to hold a vertical load safely in place.
Quick checklist
- ✓ Required force at your working pressure
- ✓ Stroke and mounting space
- ✓ Port/thread type (PT / G / NPT)
- ✓ Magnet (-S) for sensors?
- ✓ Back cover (CA/U/CM) & mount (LB/FA/SDB/TC)
Installation & Maintenance Notes
- check Use clean air filtered to 40µm or finer.
- check Keep within 0.15 – 1.0 MPa operating pressure.
- check Avoid side load on the piston rod.
- check Do not dismantle the riveted front/back covers.
- check Use correct back cover (CA/U/CM) & mount (LB/FA/SDB/TC).
- check Installation by qualified personnel per AirTAC docs.
Airtac MFJ Adjustable Mini Cylinder MFJ40X40-20S FAQ
This 40 mm bore cylinder features a 1/4" port, a 16 mm rod, and an M14x1.5 male rod thread. It delivers 628.3 N push and 527.8 N pull at 0.5 MPa, 879.6 N push and 738.9 N pull at 0.7 MPa, with a theoretical maximum of 128.1 kgf at 1.0 MPa.
The external adjuster shortens the extend stroke by up to 20 mm on site, giving a usable extend range of 20-40 mm, while fixed TPU bumper pads absorb end impacts. The -S suffix means a piston magnet is built in for CMSG, DMSG, or EMSG switches; a SKU without S cannot take a sensor.
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1-Year Warranty
Covers non-human-caused product damage.
Fast Dispatch
Standard models are processed and dispatched in 3-5 business days.
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Most inquiries answered within 7-8 hours.
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